1. Field of the Invention
The present disclosure relates to a magnetic contactor, and more particularly, to a driving circuit for magnetizing a magnetic coil of a magnetic contactor. The magnetic coil driving circuit of the magnetic contactor according to the present disclosure can detect an increase in temperature inside the magnetic contactor and prevent damage to, and rapid lifespan reduction of, the magnetic contactor and an electric load connected thereto.
2. Background of the Invention
A magnetic contactor is connected to an electric circuit (hereinafter referred to as a circuit) between an electric power source and an electric load such as a motor supplied with electric power from the electric power source and is configured to open or close the electric circuit depending on whether a switching control signal is applied. Accordingly, the magnetic contactor is used as a control means for running or stopping the load such as a motor by connecting or breaking an electric power circuit to the load.
A magnetic contactor is configured to magnetize or demagnetize a stationary core disposed around the magnetic coil according to magnetization or demagnetization of the magnetic coil to attract or repel a movable core movably installed at a location facing the stationary core by magnetic force, thus bringing a movable contact connected to the movable core in contact to a corresponding stationary contact to operate as circuit closing or separating the movable contact from the corresponding stationary contact to operate as circuit opening.
In such a magnetic contactor, a magnetic coil driving circuit is a driving circuit for magnetizing or demagnetizing the magnetic coil and is configured to include various kinds of analog components.
That is, the magnetic coil driving circuit includes various electrical components such as a magnetic coil, a capacitor, a semiconductor switch, etc.
However, the components consume electric power while operating, and consumed electric power generates heat a limited space inside the magnetic contactor, which causes a problem of deterioration of a corresponding component and a problem of damage to a corresponding component and its ambient components.
In particular, the driving circuit for driving the magnetic coil for the magnetic contactor may accurately perform its functions only when electrical sub-components maintain their own electric characteristics.
However, when temperature inside an electric power distribution board in which the magnetic contactor is installed increases or when temperature inside the magnetic contactor continuously increases since an overvoltage is continuously applied to an electric power source input terminal of the magnetic contactor, a conventional magnetic contactor does not have any protection circuit, thus resulting in a lifespan reduction or a burn-out of the magnetic contactor and also a risk for damage to the load (e.g., a motor) connected to the magnetic contactor.